The present invention relates to a method and apparatus for withdrawing a sample from or delivering a substance transdermally to a patient. More particularly, the invention is directed to a method and apparatus for withdrawing a sample from or delivering a substance to successive patients using a device having a plurality of skin penetrating devices.
Drugs and various pharmaceutical agents are delivered to the body by many known methods. One method that is often used for the subcutaneous delivery uses a needle or other cannula. The use of a cannula is an effective method of delivering a drug. However, the pain typically experienced by the patient has prompted the development of alternative methods for delivering drugs.
Various devices have been proposed for the transdermal delivery of substances to the body and for withdrawing a substance from the body in a manner that is less painful to the patient. Transdermal delivery devices are often used to provide a sustained release of the substance to maintain a desired rate of delivery. Many transdermal delivery devices do not administer the drug at a sufficient rate to be used effectively. Moreover, many drugs can not be delivered transdermally since the drugs are not able to pass through the protective skin layers.
The skin is made up of several layers with the upper composite layer being the epithelial layer. The outermost layer of the skin is the stratum corneum that has well known barrier properties to prevent molecules and various substances from entering the body and analytes from exiting the body. The stratum corneum is a complex structure of compacted keratinized cell remnants having a thickness of about 10-30 microns. The stratum corneum forms a waterproof membrane to protect the body from invasion by various substances and the outward migration of various compounds. The natural impermeability of the stratum corneum prevents the administration of most pharmaceutical agents and other substances through the skin. Numerous methods and devices have been proposed to enhance the permeability of the skin and to increase the diffusion of various drugs through the skin to be utilized by the body.
One type of device that has gained attention in recent times is the micro device that is able to penetrate the outer layers of the skin with less pain or discomfort than a standard cannula. These micro devices typically have needles that are a few microns to several hundred microns in length. The micro devices for delivering drugs through the skin form micro pores or cuts through the stratum corneum. By penetrating the stratum corneum and delivering the drug to the skin in or below the stratum corneum, many drugs can be effectively administered. The devices for penetrating the stratum corneum generally include a plurality of micron size needles or blades having a length to penetrate the stratum corneum without passing completely through the epidermis. Examples of these devices are disclosed in U.S. Pat. No. 5,879,326 to Godshall et al.; U.S. Pat. No. 5,250,023 to Lee et al., and WO 97/48440.
Transdermal drug delivery is also known to use pulsed laser light to ablate the stratum corneum without significant ablation or damage to the underlying epidermis. A drug is then applied to the ablated area and allowed to diffuse through the epidermis.
The delivery of drugs through the skin can be enhanced by either increasing the permeability of the skin or increasing the force or energy used to direct the drug through the skin. One example of a method for increasing the delivery of drugs through the skin is iontophoresis. Iontophoresis generally applies an external electrical field to ionize the drug, thereby increasing the diffusion of the drug through the skin. Iontophoresis can be difficult to control the amount and rate of drug delivery. Under some circumstances, iontophoresis can cause skin damage depending on the extent of ionization, the energy applied to ionize the drug and duration of the treatment.
Sonic, and particularly ultrasonic energy using a piezoelectric crystal, has also been used to increase the diffusion of drugs through the skin. Although numerous efforts to enhance drug delivery using sonic energy have been proposed, the results generally show a low rate of drug delivery.
The prior methods and apparatus for the transdermal administration of drugs can be cumbersome to use and have exhibited limited success. Accordingly, a continuing need exists in the industry for an improved device for the administration of various drugs and other substances thought the skin of a patient.
The present invention is directed to a method and apparatus for withdrawing a substance or delivering a substance to a patient, such as a drug, vaccine or other pharmaceutical agent. In particular, the invention is directed to a method and apparatus for withdrawing a substance though the skin or delivering a substance to the skin to a sufficient depth where the substance can be absorbed and utilized by the body. In embodiments of the invention, the substance to be delivered is a dry drug that can be reconstituted and introduced into the intradermal tissue below the stratum corneum where the substance can be absorbed.
Accordingly, a primary object of the invention is to provide a method and apparatus for efficiently withdrawing a substance or administering a substance transdermally to several patients without risk of cross contamination between patients.
Another object of the invention is to provide a device having a plurality of skin penetrating devices for penetrating the stratum corneum of the skin and withdrawing a substance from or delivering a substance to the skin.
A further object of the invention is to provide a device for delivering a vaccine where the device has a plurality of skin penetrating devices that can be sequentially presented for successive delivery to several patients.
Another object of the invention is to provide a method and apparatus for transdermally withdrawing a sample from a patient or delivering a substance to a patient using a device having a plurality of spaced apart needle arrays where each needle array can be advanced to an operating position for each patient.
Another object of the invention is to provide a device for delivering a substance to a patient without requiring a separate reconstituting or reformulation step.
Still another object of the invention is to provide a transdermal sampling or delivery device having a web with a plurality of spaced-apart skin penetrating devices and an advancing device to present a clean and sterile skin penetrating device for sampling or delivering a substance to successive patients.
A further object of the invention is to provide a device for the transdermal sampling or delivery of a substance to a patient where the device has a plurality micro needle arrays and a dried substance on the micro needles where the device can deliver the substance to successive patients.
These and other objects of the invention are substantially attained by providing a device for sampling or delivering a substance to a patient where the device has a support with a bottom wall. The support houses a flexible web having a plurality of skin penetrating devices attached to the web. The web is mounted within the support in a manner to supply the web and the skin penetrating devices across an outer face of the bottom wall with the skin penetrating devices facing outwardly from the support in a position to be available for penetrating the skin of a patient. Generally an advancing device is included to advance the web and the skin penetrating devices though the support. The skin penetrating device has a length sufficient to penetrate at least the stratum corneum of the skin. In one embodiment the skin penetrating device pierces the stratum corneum.
The objects and advantages of the invention are further attained by providing a delivery device for administering a substance through the skin of a patient. The device comprises a support having a top end, a bottom end and a bottom wall at the bottom end. A supply member supporting a web with a plurality of skin penetrating devices is mounted within the support. Each of the skin penetrating devices has a substance to be delivered to the patient. An advancing assembly is included to advance the web and the skin penetrating members incrementally across the bottom wall to expose the skin penetrating members and position the skin penetrating members in a position for delivering the substance to the patient. A recovery device is provided to receive the web after the skin penetrating member is used.
Another object of the invention is to provide a method of withdrawing or administering a substance through the skin of a patient, the method comprising providing a device having a support with a top end, a bottom end, and a bottom wall, a supply member for supporting a web having a plurality of skin penetrating members, an advancing assembly for incrementally advancing the web from the supply member across the bottom end of the support to a recovery member, wherein each skin penetrating member is available for penetrating the skin of a patient when positioned on the bottom wall of the support, the method comprising advancing the web to expose a penetrating member on the bottom wall, pressing the skin penetrating member against the skin of a patient, and delivering or withdrawing a substance to the patient.
The objects, advantages and other salient features of the invention will become apparent from the following detailed description which, taken in conjunction with the annexed drawings, discloses preferred embodiments of the invention.